On levels of detail in terrains

Abstract

In many applications it is important that one can view a scene at di erent levels of detail. A prime example is ight simulation: a high level of detail is needed when ying low, whereas a low level of detail su ces when ying high. More precisely, one would like to visualize the part of the scene that is close at a high level of detail, and the part that is far away at a low level of detail. We propose a hierarchy of detail levels for a polyhedral terrain (or, triangulated irregular network) that allows this: given a view point, it is possible to select the appropriate level of detail for each part of the terrain in such a way that the parts still t together continuously. The main advantage of our structure is that it uses the Delaunay triangulation at each level, so that triangles with very small angles are avoided. This is the rst method that uses the Delaunay triangulation and still allows to combine di erent levels into a single representation.